import { FormControl } from '@angular/forms'; export function validateUrl(c: FormControl) { let URL_REGEXP = new RegExp('^https?://(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)$'); return URL_REGEXP.test(c.value) ? null : { validateUrl: { valid: false } }; }